move transform gizmo to selected vertex in edit mode
If you hit Shift + S in Edit Mode, you can &quot;snap (the crosshairs 3D) cursor to selected&quot;. Then change the center of your rotation to &quot;3D Cursor&quot; using the little figure eight-like icon near the magnet towards the top of your screen. (You can also reach &quot;snap cursor&quot; via Object &gt; Snap &gt; &quot;Cursor to Selected&quot; in Object Mode.) If that doesn't put the gizmo in the middle of all your selected vertices, then you can try Object &gt; Set Origin &gt; Origin to 3D Cursor in Object Mode.
Incidentally, it looks like you have a mass of vertices selected. Try zooming in really close to select just one vertex.